A Study on Prediction Method of Time-Dependent-Change of Viscosity for Cement Paste Used Polycarboxylate Based Superplasticizer

Time-dependent-change of flowability of fresh concrete is very important for developping concrete practice design method. In this study, in order to develop a predicting method of the change of viscosity for cement paste used polycarboxylate based superplasticizer referencing Hattori-Izumi theory, time-depending-change test of cement paste was carried out. The main factors of this experiment was type of powder. For lime powder which is not active powder, viscosity kept steady with time. It was considered that this result was what the theory of potential had expected. On the other hand, viscosity changed with time for ordinary portland cement which was chemically active powder. A prediction model of time-dependent-change of viscosity for cement paste was developped assuming apparatus potential energy between two cement particle from experimental test result. It was considered that the model could predict viscosity-change for temperature effect and for using high early strength cement on the whole.